A Combined Experimental and Theoretical investigation of reactive flow in brittle media with applications to solid Earth geodynamics

在自然界和工程世界中，许多重要的过程都涉及到流体渗透到材料中，然后发生反应，形成体积大得多的新材料。这些巨大的体积变化反过来又被认为会诱发压裂，从而为流体渗透开辟了新的途径，可能会导致一系列普遍破裂的材料，这一过程被称为？反应引起的开裂？虽然许多自然系统提供了这些过程的间接证据，但对这些机制的物理和效率（或者它们是否有效）知之甚少。本提案的目的是通过结合实验室实验，理论和先进的脆性材料计算模型，发展对反应性开裂过程的基本理解。更好地了解这些过程可能会导致新的工程方法，用于有效的碳封存或碳氢化合物提取，可以深入了解诱发地震活动以及自然世界中重要的地球科学过程。在此期间，我们将把简化系统的实验室岩石力学实验与计算模型结合起来，这些计算模型可用于直接根据实验测试和验证一系列流体力学破坏理论。实验室实验将在拉蒙特进行？S三轴变形仪，控制流体流动，监测应力、孔隙压力、声发射和渗透率变化。实验将研究水合和脱水反应的模拟材料选择提供大体积变化的简化几何。我们将探索在不同围压水平下，材料嵌套圆柱体的行为，内部有一个反应性圆柱体，可以产生或摄取含水流体，周围有一个脆性岩石的外部圆柱体。建模将是哥伦比亚大学多个部门和学院的合作成果，并使用pi开发的开源计算框架。实验的直接建模将为测试假设、验证理论和校准本构关系和失效模型提供所需的控制。然后可以扩展改进的流体-脆性-固体相互作用理论模型，以探索它们对大尺度地球动力学的影响，例如通过俯冲带的挥发性循环。

Many important processes in the natural and engineered world involve the infiltration of fluids into materials that then react to form new materials with significantly larger volume. These large volume changes, in turn are thought to induce fracturing which opens up new avenues for fluid infiltration, potentially leading to a cascade of pervasively cracked materials in a process dubbed ?reaction induced cracking?. While many natural systems give indirect evidence of these processes, very little is understood about the physics and efficiency of these mechanisms (or if they even work). The purpose of this proposal is to develop a fundamental understanding of the reactive cracking process by combining laboratory experiments, theory and advanced computational models of reactive brittle materials. A better understanding of these processes could lead to new engineering methods for efficient carbon sequestration or hydrocarbon extraction, could give insight into induced seismicity as well important Earth science processes in the natural world.During this award, we will combine laboratory rock mechanics experiments on simplified systems with computational models that can be used to test and validate a range of hydro-mechanical failure theories directly against the experiments. Lab experiments will be conducted in Lamont?s tri-axial deformation apparatus, with control of fluid flow and monitoring of stresses, pore pressures, acoustic emissions and permeability changes. Experiments will investigate both hydration and dehydration reactions on analog materials chosen to provide large volume changes in a simplified geometry. We will explore the behavior of nested cylinders of materials with an interior reactive cylinder that can either produce or ingest hydrous fluids, surrounded by an outer cylinder of brittle rock under various level of confining pressure. The modeling will be a collaborative effort across multiple departments and schools at Columbia and use an open-source computational framework developed by the PIs. Direct modeling of the experiments will provide the needed control for testing hypotheses, validating theories, and calibrating constitutive relations and failure models. Improved theoretical models of fluid-brittle solid interaction can then be extended to explore their consequences for large-scale geodynamics such as volatile cycling through subduction zones.